You do not appear to be in the packager group which means, you do not have ssh access to dist-git.
You can however push to dist-git via http using fedpkg.

This is documented here: https://docs.fedoraproject.org/en-US/ci/pull-requests/#_you_are_not_a_packager

Thank you for the advice.

The following section in .git/config helped me to sove the problem.
[credential]
helper = /usr/bin/fedpkg gitcred
useHttpPath = true

$ git remote -v
fork https://src.fedoraproject.org/forks/mmalik/tests/selinux.git (fetch)
fork https://src.fedoraproject.org/forks/mmalik/tests/selinux.git (push)
origin https://src.fedoraproject.org/tests/selinux.git (fetch)
origin https://src.fedoraproject.org/tests/selinux.git (push)
$

git push -u fork ... works again

if you do clone via fedpkg or do fedpkg push the [credential] section will be automatically added for you, so you would only need this the first time.

Glad you got it working!

Let us know if we can help further :)